Flow Modification Properties of Ceramic Foam Filters-A Summary of Recent Work

摘要

The ability of ceramic foam filters to remove oxides and other inclusions from the molten metal stream as it fills steel castings is widely accepted and has been confirmed repeatedly through post-pouring evaluation of solidified castings. It has also been known that the ceramic foam filter minimizes the formation of reoxidation inclusions through metal flow modification and reduction of turbulence from the metal stream as it enters the casting. However, until recently, the flow modification capability of filters has only been implied by water modeling and computer simulations of molten metal velocity and turbulence. Through refinements in the use of real-time X-ray techniques to study the ferrous casting process, it has become possible to see and record the effects of various gating and filtration configurations on molten ferrous metal flow and to confirm the validity of computer simulations. This paper summarizes recent work in the field of foam filtration knowledge. Included in this paper are: A review of initial work in the use of real-time x-ray procedures to examine the effect of filtration and various gating arrangements on simple plate castings A summary of recent work showing dynamic computer simulations of fill profile characteristics to determine fill times and optimum methoding Previously reported examples of real-time X-ray images to confirm the validity of computer simulations and the effect of filters on casting filling characteristics and flow modification Comparisons of previously documented computer simulation results to real-time X-ray images of the same castings.